I'll move this topic over to the Game Help board, as the Game Discussion board is for general discussion surrounding the game and its elements, as opposed to seeking assistance for a problem.
When you open the application, does the game freeze or do you receive any kind of error popup? Do you recall downloading anything recently?
If it's freezing, you could be experiencing a duplicate particle problem. Open up your Feral Heart files, and go FeralHeart >> media >> particles, and delete any file ending in _0, _1, etc. For some reason, the game can add in extra particles that can cause your game to crash.
Re-installing the game will most likely be an easy solution, but be sure to save a backup folder for any files that you'd like to keep (such as screenshots, presets, etc) in a folder outside of your current FeralHeart folder.
